Some time ago, I had to convert all tables of a database from
MyISAM to InnoDB on a new server. The plan was to take a logical
dump on the master, exporting separately the schema and the data,
then edit the CREATE TABLE statements to ensure all
tables are created with InnoDB, and reload everything on the new
server.

Quite easy, isn’t it? Of course I wanted to run a test first
before performing the actions on a live system.

So let’s play with the sakila database.

mysqldump has options to export schema and data separately, let’s
use them:

Recently, someone emailed me:I have a requirement in MYSQL as
follows:
we have a table EMP and we have to restrict the
users not delete employees with DEPT_ID = 10. If
user executes a DELETE statement without giving any
WHERE condition all the rows should be deleted
except those with DEPT_ID = 10.

We are trying to write a BEFORE DELETE trigger but
we are not able to get this functionality.

In a previous article, I've already talked about an optimized way
to connect locations in a geographic point of view by
using MySQL. In this manner, locations of pubs, drugstores,
barbers or even users can be obtained. Communities, or perhaps I
should use the newer term Social Networks, make use of the buddy
network of indiviual members in addition to the geographical
mapping. This has many psychological advantages, because new
members can be integrated in an established network very easily
and I'm more willing to become involved when I already know some
of the members.

The latest MySQL 5.5 milestone release offers
support for an ANSI/ISO standard feature called the
SIGNAL syntax. You can use this syntax
inside stored routines (including triggers) to raise an error
condition which can be used to invoke specific error handling, or
otherwise abort the stored routine. In addition, you can use the
SIGNAL syntax to convey information about what went
wrong, which may be used by the caller to handle the …

Looking at Bug#47310, which is a feature request that I hear
frequently when I talk about partitions, I wrote a comment,
suggesting triggers to work around the limitation.
The reason for the limitation is that allowing arbitrary
functions for partitioning was too complex and it was provoking
crashes and other unpleasant side effects (see the discussion
under bug#18198).
But if you use a trigger, the resulting column is a plain
integer, and many of the side effects disappear. The drawback is
that you …

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